Reset device for turn signal reset switch with trigger finger tensioned by a compression spring

ABSTRACT

A reset device for a blinker switch includes a pivoting reset element which is used which has two lateral arms on which opposing springs extending through the switch housing act. These springs both tension the reset element with respect to the steering spindle and produce a torque tending to restore the reset element to its middle setting. The problem of the invention is to do without the conventional draw springs. The invention solves this problem by means of a single compression spring acting on the reset element and providing both a force in the longitudinal direction of the reset element and the desired restoring torque.

TECHNICAL FIELD

The invention pertains to a reset device with overshift protection for aturn signal reset switch in motor vehicles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turn signal reset switches of this kind are located near the steeringwheel on the steering column and the automatic reset from one of the twoswitched-on settings into the neutral middle setting takes place bymeans of a trigger finger located on the switch, and extending into thecircular path of a cam located on the steering spindle.

A reset device of this kind is known, for example, from DE-PS 2,826,597.A similar unit is also described in DE-OS 3,502,650 and also in DE-PS2,914,742.

For all these known systems, it is important that the trigger finger betensioned against the steering spindle, and also that it be aligned byspring force in its standard position, with the trigger finger pointingtoward the steering spindle in the standard position.

In the reset device described in DE-PS 3,502,650 and also in all theother above-referenced devices, the trigger finger is tensioned in sucha manner that two coil springs, attached to one end of it at the switchhousing, engage symmetrically in two lateral lugs of the trigger finger.Both springs having a common force component toward the steering column,whereas the torque exerted by both springs jointly onto the triggerfinger tends to pull it into its standard position.

A disadvantage in the known reset devices is that the two springs actingon the trigger finger tend to make noise and are comparatively bulky,since they extend through a significant region of the interior of thehousing. In addition, the attachment of the four ends of these springsrequires an additional effort which cannot be automated, in particular,when the accidental release of one of these springs from one of themounting points is to be dependably prevented.

Therefore, it is the purpose of the invention to specify a reset unit ofthe kind specified above, which is of simple design and does not needthe reset devices described above nor the two tension springs acting inopposite directions and constructed as draw springs.

The present invention does not use the aforementioned two draw springs,but instead uses a single compression spring, which will also act with aflat contact surface on the flat contact surface of the guide lug. Theadded advantage of the present invention is that the guide lug is alwaystensioned against the steering spindle. On the other hand, care is takenthat in a pivot movement of the trigger finger--due to thesimultaneously pivoted contact surface of the trigger finger against theflat contact surface of the spring--the spring's point of contact ismoved from the middle line of the trigger finger and thus an additionaltorque is applied by the compression spring, which attempts to returnthe trigger finger into its standard position.

In order to ensure that the contact surface for the guide lug is aslarge as possible with respect to the spring, and on the other hand, inorder not to prevent a potential pivot motion of the guide finger, in arefinement of the invention the guide lug 11 is square having sidesurfaces adjoining the lateral groove walls 10 having an arc-shapedcontour. This further allows the side surfaces of the guide lug toengage, on the one hand, essentially in a line with the side surfaces ofthe longitudinal groove. On the other hand, due to the arc-like contourof the side surfaces, a pivot motion of the trigger finger will not beprevented.

In order to make the contact surface of the spring as large as possiblewith respect to the guide lug and thus to obtain the greatest possibletorque for a specified groove width during a pivot motion of the triggerfinger, in a refinement of the invention, the radius of the side surfaceis curved like an arc sector is smaller than or equal to one-half thewidth of groove 10. Accordingly, the contour of the guide lug coincideswith sections of a circle whose circumference is in contact with theside walls of the groove.

In order to achieve a standard position of the trigger finger alignedprecisely with the middle of the steering spindle, in a refinement ofthe invention the end of the spiral spring facing the guide lug 11 isflat. Accordingly, preferably the end of the spiral spring facing thetrigger finger is ground off smooth, so that a ring-shaped contactsurface of the spring lying in a plane will be obtained on the guidelug.

Now in order to prevent the edges of the spring from damaging the planeof the guide lug and in order to improve the contact surface of thespring with respect to the guide lug, in a refinement of the inventionthe end region of spiral spring 13 facing the guide lug is held in acasing 14 run in the longitudinal groove 10 which has a base surfacepointing to the guide lug. Accordingly, the end of the spring facing theguide lug does not act directly on the guide lug, but rather by means ofa casing, so that the spring forces are distributed uniformly onto asurface.

One particularly simple design for the casing is that the casing is madeof plastic and runs through the side walls of the longitudinal groove.In this case, due to the casing it will also be assured that the springcannot slip out in any manner. As was explained farther above, the endof the spring turned away from the guide lug is braced directly againstthe switch housing or against a fixed-position component opposite theswitch housing. Now in order to prevent the end braced against thehousing from slipping off to the side due to the forces acting on thespring, a pin is used.

The present description makes express reference to the state of the artdisclosed above and in particular to DE-OS 3,502,650. Therefore, thefigures will explain the components only to the extent necessary inconjunction with DE-OS 3,502,650.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial and cut-away representation of a section from areset device.

FIG. 2 is a cross section along line A through the reset deviceaccording to FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a portion of a switch lever 2 which is securely attached toa switching element 3. The switch lever 2 is braced elastically againstthe switching element 3 by means of a spring casing 4. In a pivot motionof the switch lever 2 about the pivot axis P, the switching element 3pivots about a corresponding angle.

Within the switching element 3 there are two slide elements 5 which canslide transversely in reference to the plane of the paper and are keptapart by the force of an installed compression spring 19. The slideelements are braced against a catch contour 20 by means of moving catchelements 21 at the housing 6.

The switching element 3 features a triangular protrusion 7 and aprotrusion 8 of the reset element 9 is braced against it. The resetelement 9 can slide within and pivot in a longitudinal groove 10 of thehousing 6 when a guide lug 11 engages in the groove.

In the symmetrical position of the reset element 9 illustrated in FIG.1, this element rests with its protrusion 8 on the pointed edge 12 ofthe triangular protrusion. Thus, a coil spring 13 exerts a downwardforce onto the guide lug 11 by means of a casing 14 with the basesurface of this casing 14. Now, if the protruding triangle 7 is pivotedtoward or away from an observer due to a pivot movement of the switchlever 2, then the point of contact 12 of the protrusion 8 is shifteddownward from the lateral edge of the triangular protrusion 7, so that,due to the force of the spring 13, the reset element 9 moves downward byan amount specified by the pivot motion of the switch lever 2. Thiscauses a trigger finger 15 at the lower end of the reset element 9 toarrive at the engaging area of a cam 17 on the steering spindle 18. Now,as is explained in detail in the state of the art reference above, thereare two possible sequences. If the steering spindle 18 rotates in afirst direction, then the reset element 9 will turn about the guide lug11 until the cam 17 on the steering spindle 18 can pass the lower end ofthe trigger finger 15.

But if the steering spindle 18 rotates in the opposite direction, thenthe cam 17 engages in the trigger finger 15, whereupon the reset elementengages in the slide piece 5 and releases it from its locked actuationposition and thus returns it to its middle setting. This concludes theturn signal process and the turn signal lever is returned to its middlesetting. It is important for the invention due to the action of thespiral spring 13 in conjunction with the casing 14, as is indicated inFIG. 2, not only to exert a downward force, but at the same time, alsoto apply a torque which attempts to bring the reset element 9 into itsstandard, middle position by means of the guide lug 11. For example, ifthe trigger finger is pivoted by the cam 17 of the steering spindle 18,then at the same time, the guide lug 11 is tilted against the basesurface of the casing 14. Thus the casing engages eccentrically in theguide lug 11, which leads to a restoring torque. Thus in a simplemanner, the function of the known, two tension springs is replaced by asingle, spiral compression spring.

In order to simplify the rotation of the guide lug 11 in the groove 10(see FIG. 2), the side surface of the guide lug 11 is of ball shape andpreferably has a circular contour. The circular curvature should beselected so that the radius of curvature is only somewhat smaller thanhalf the width of the groove. If it is larger, there is a danger ofsticking; if it is smaller, then there will be free play in the pivotposition. The large contact surface should be achieved by bringing theflat surface as close as possible to the plane of symmetry of therecess.

In order to prevent a lateral shifting of the end of the spring 13turned away from the casing base of the casing 14 with respect to thehousing 6, a pin 16 extends from the housing 6 into the end of thespring.

We claim:
 1. A reset device with a switching cutout for a turn signalreset switch for use in motor vehicles, wherein the turn signal resetswitch is located in a housing, said reset device including an automaticreset into a middle setting which takes place by means of a triggerfinger located on the switch, wherein said trigger finger extends in alongitudinal direction perpendicular to a steering spindle and, uponactuation of the switch, engages a cam located on the steering spindleand is pretensioned against the steering spindle by spring force;wherein said trigger finger cooperates with a switching element which ispivoted about an axis parallel to the steering spindle and is equippedwith a catch element engaging in a catch contour, comprising:means forrotating said trigger finger wherein said rotating means is mounted soas to rotate in the housing of the switch an can be displaced therein inparallel to the longitudinal direction of the trigger finger, having aguide lug that extends into a groove in the housing, the grooveextending in the longitudinal direction of the trigger finger and havinga width, a spiral spring braced against the housing which acts in thelongitudinal direction of the trigger finger on a contact surface of theguide lug and thus tensions the trigger finger, wherein the contactsurface of the guide lug facing the spiral spring is a flat surfacepositioned vertical to the longitudinal direction of the trigger finger.2. The reset device according to claim 1, wherein the guide lug isessentially a square having side surfaces with arc-shaped contours. 3.The reset device according to claim 2, wherein the arc-shaped contourshave a radius smaller than or equal to half the width of the groove. 4.The reset device according to claim 2, wherein the spiral spring facingthe guide lug is at least partially held in a casing run in the groove.5. The reset device according to claim 1, wherein a pin, which securesthe spiral spring against a lateral movement, extends from the housingin the direction in which the groove extends.